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Alphacast High Frequency CPI - August 17th to 23th 2026

Alphacast High Frequency CPI
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Alphacast High Frequency CPI: Inflation was 0.21% WoW

Weekly inflation accelerated in the third August reading. Consumer prices rose 0.21% WoW, up from a revised 0.14% in the previous week. Despite the weekly acceleration, the monthly run rate continued to ease, declining to 1.2% MoM from a revised 1.5%, while annual inflation remained broadly stable at 31.5% YoY versus a revised 31.5%.

The weekly acceleration was driven by stronger seasonal and core price dynamics, while regulated prices slowed markedly. Seasonal prices rose 0.26% WoW, up from a revised 0.13%, while core inflation increased 0.24% WoW from a revised 0.06%. In contrast, regulated prices slowed to 0.12% WoW from a revised 0.31%. On a monthly basis, however, inflation moderated across all three components: seasonal inflation declined to 1.8% MoM from a revised 2.3%, core inflation to 1.4% from 1.6%, and regulated inflation to 0.5% from 0.8%.

Overall, the third August reading showed a pickup in weekly inflation, driven by firmer seasonal and core prices, partly offset by a significant slowdown in regulated prices. At the same time, the headline monthly run rate extended its downward trend to 1.2% MoM, with moderation across all major components. Annual inflation remained virtually unchanged at 31.5% YoY.

Methodological update

Weeks ago, Alphacast updated the methodology of its High-Frequency Inflation Index. The price sample was expanded by more than 300%, while estimates for the previous 12 months were revised following improvements in price sampling and classification procedures. These changes are strictly statistical rather than econometric and do not modify the underlying conceptual framework of the index.

As a result, the root mean squared error declined from 0.45 pp to 0.29 pp for headline inflation and from 0.71 pp to 0.46 pp for core inflation. This represents a reduction in estimation error of approximately 35% and 36%, respectively.

To illustrate the impact of the methodological update, under the previous methodology July headline inflation would have been estimated at 1.22% MoM, compared with 1.73% MoM under the updated methodology. Similarly, core inflation would have been estimated at 0.93% MoM, compared with the current estimate of 1.59% MoM. This represents an upward revision of approximately 0.52 pp for headline inflation and 0.66 pp for core inflation.

These differences reflect the expansion of the price sample and improvements in sampling and price-classification procedures, rather than a change in the underlying price dynamics observed during the month.

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